The present invention relates to a self-supporting composite plate for double floors, ceilings or the like, with a pan-shaped outside wrapper member and a hardenable mineral filler, e.g., anhydrite, which is introduced in liquid state into the pan-shaped wrapper member, and in which are embedded light construction materials in order to minimize weight.
A self-supporting composite plate of this type is known from German Pat. No. 2 004 101. Wood-reinforced concrete is one example of a mineral pan-filling material containing light construction materials, which is obtained by mixing wood fibers with liquid concrete in such a manner that the wood fibers are distributed substantially uniformly in the hardened concrete. The drawback of a composite plate with such a pan-filling material is that it is of insufficient strength and bending resistance for many uses. Also, the use of wood-reinforced concrete as a pan filling material leads to finished composite plates of low fire-resistance.
In concrete technology, it is generally known to embed light construction elements, e.g., of expanded clay, in concrete elements for weight reduction. When this method is used for the construction of a self-supporting composite plate of the aforementioned type, the great danger arises that the relatively light expanded clay bodies or the like will accumulate in the same area of the liquid mineral filler material, e.g., anhydrite, following its introduction into the pan-shaped wrapper member. Because of the relatively high degree of buoyancy common to this material, all of the filler particles accumulate in the top area and are embedded there. This results in diminished strength, particularly on the filler material surface, and reduced bending resistance in comparison to a composite plate with a homogenous anhydrite filling.